1. Field of the Invention
The present invention relates to a method of extracting a visual descriptor using a feature selection, and a system for the same.
2. Discussion of Related Art
A technology of generating a visual descriptor based on a feature point extracted from an image and matching the visual descriptor with another visual descriptor has been applied to various computer vision techniques, such as object recognition and detection, content based image retrieval, and video tracking, and much research on this technology is being conducted.
As a result of the emergence of smartphones, the amount of multimedia content being proliferated is expanding, so there is an increasing demand for technologies related to the above described computer vision, to effectively search and consume the content. In particular, it is difficult to enter text on a smartphone, which has led to a need for content based image retrieval technology in which a search is performed using an image as an input, and has also caused a search application using a feature based image processing to be developed more actively.
The feature based image processing is divided into a global feature based technology and a local feature based technology using a feature point. The local feature based image processing using a feature point is being spotlighted with its high performance in various environments.
Examples of the local feature based image processing technique using a feature point may include scale-invariant feature transform (SIFT) and Speeded Up Robust Features (SURF). In both SIFT and SURF, a point having a local maximum or minimum of local region filtering is detected as a feature point in a scale-space, and a feature descriptor is extracted using a local neighbor region surrounding a feature point. These techniques require great amounts of computation and memory for a visual descriptor extraction process and a matching process, and the visual descriptor has a size larger than that of a JPG image normalized to a resolution of 640*480, which is, in this respect, not suitable for a mobile visual search or large scale image retrieval that deals with several millions of images.
The related art of the present invention is disclosed in Korean Patent Publication No. 10-2009-0113617.